TV Field Production. Camera Basics Mary Walbridge

Transcription

1 TV Field Production Camera Basics Mary Walbridge

2 Camcorder An electronic camera Lens Camera with imaging device Viewfinder Build in DVR- digital video recorder

3 How Camera works Camera is an imitation of the human eye..like the eye it sees, by means of a lens which gathers light reflected off objects The lens directs this light onto a surface which senses the pattern formed by the differences in brightness and color of the different parts of the scene. In the eye this surface at back of eye sends the pattern of light to the brain where it is translated into an image which we see

4 IN the camera--- The lens directs the patterns of light onto sensitive surfaces Film Cameras- record light patterns on film coated with light -sensitive chemicals. Chemicals react to form an image. After film is processed in other chemicals the image becomes visible. The eye and camera lens ( both convex) always convert images. Turn the light pattern upside down as it passes through

5 In digital cameras-- Both still and video the lens focuses light patterns onto an image sensor Either a CCD ( charge coupled device) Or a CMOS ( Complementary metal oxide semiconductor) The surface of the sensor contains from thousands to millions of tiny light- sensitive areas called picture elements or pixels

6 Movie Cameras Record Images.. IN THE SAME WAY THAT STILL CAMERAS DO BUT THEY DO IT MORE OFTEN 8 Millimeter movie camera take 18 pictures or frames per minute 16 & 35 Millimeter (mm) movie cameras take 24 frames per second (FPS) Video Cameras record images-or take 25 or 30 frames per second (FPS)

7 Persistence of vision The illusion of continuous movement created by the viewer s mind filling in the gaps between the individual frames To perceive the separate pictures or frames as continuous movement is know as persistence of vision

8 Camera Lens Exposure, Aperture and F-stop Exposure is the amount of light that comes through the lens and hits the film or CCD chip The hole in the center of the lens that the light travels through is called the aperture. If the hole is big it lets in a lot of light, and the f-stop # is smaller like f-2 If the hole is small it lets in very little light, and the f-stop # is larger like f- 16

9 The iris is the part of the camera that has an adjustable opening to allow light to enter and fall upon the image plane (i.e. the sensor CCD, film, etc). The aperture is the size of the opening in the iris.

10 F/stop numbers The size of the aperture is adjusted by the f/stop ring on the outside of the camera The f/stop is a measure of how big or small the aperture Think of f-stops as fractions, because that is what they are F2 maximum light acquisition or for low light situations F16 or F22 minimum light acquisition for full sun or lots of light situations From F2 aperture each stop down delivers half as much light as the lower number which precedes it f/1-f/1.4/ f.2- f/2.8 f/4- f/5.6 f/8 f/11- f/16 - f/22 f/32- f/45- f/64

11 Color Temperature Light comes in different colors Red glow of open fire or sunset Bluish cast of a sky with dark rainclouds Blue-green glow for fluorescents Color films and CCD/CMOS chips can handle only one color of light source at a time. by means of color temperature and color temperature

12 Color temperature Is a way to identify different colors of light sources. Color temperature is measured I degrees Kelvin named after Britain s Lord Delvin who devised the system 2000K is the reddish light produced at 2000 degrees Kelvin 8000K is a bluish light produced at 8000 Kelvin

13 Color Temperature Though our eyes adjust to these different color light sources the camera doesn t and it can handle only one source of light at a time and reproduce colors accurately. To take a picture under different colored light sources color filters are used to convert the existing light to the color temperature required

14 Professional video cameras Have built in filters: Tungsten-Incandescent (3200K) Mixed Tungsten and Daylight/Fluorescents (4300K) Daylight (5400K) Shade (6600K) Once you select the correct color filter on a video camera, fine tune the color by adjusting your white balance

15 White Balance Ensures that the whites in your scene reproduce as whites: the other colors fall into place

16 Setting exposure on a video camera 1. Select the correct filter and adjust your white balance 2. If the automatic exposure is on avoid large light areas and large dark areas 3. Professional cameras have both auto and manual exposure 4. For manual exposure look in viewfinder and move the f/stop ring- a good picture is one in which you can record detail in both the bright and dark areas

17 Setting exposure on a video camera 5. Most cameras viewfinders can highlight overexposed areas with non-recording zebra stripes. 6. Make a test recording under various lighting conditions and play it back 7. The main problem with video cameras is large areas of white or strong backlight shining toward the cameras from behind the subject. 8. Remove the camera or subject or both

18 ISO of film International Standards organization The ISO number indicates the speed or sensitivity of the film The lower the number the less sensitive or slower- Think 100 ASA still film used for daylight The higher the number the more sensitive or faster think 400 ASA still film used for interior shots

19 Light Meters Light meters measure the amount of light hitting them They see lights and darks not color. With most cameras with built in meters and on hand-held light meters you must manually set the ISO. Otherwise the meter won t know how much light your film requires and will give you incorrect exposure

20 Overexposure Let too much light in

21 Underexposure didn t let enough light in

22 Using a light meter On camera light meters are reflective meters This type meter measures the light reflected at the camera It averages subject which is gray and reflects 18% gray The problem is for lighter than average subjects- you have to open up your aperture For darker than average subject, close down to let less light in

23 The best way to measure light Is with a hand held incident light meter You hold the light meter s white half sphere in front of your subject, pointing toward the camera. The meter measures the light falling on a particular spot and calculates an f/stop for an average 18% subject

24 Lenses Prime Lens ( fixed) in different sizes Example of a wide is 10mm Example of normal size is 25 mm A telephoto lens example is 100 mm Zoom lens ( multi focal length ) can be set a at any number of distances Setting focus To focus, zoom in to the tightest angle possible. Focus Then pullback ( Zoom out) wide and find your final framing.

25 Depth of Field The area in front of your camera where everything looks sharp and in focus

26 Zoom Lens recommendation Camera Operator should have a zoom control and focus control MOD or Minimum object distance a camera a lens is at its closest focus limit as close as it can be and still stay in focus

27 Some shooting tips for editing Shoot scenes going beyond the action in the front and end to give the editor cutting space and choices Have clean entrances, exits, and edits for inserts. Leave time at beginning for start before subject enters scene and leave space at end before you say cut. Cover each scene with cutaways, and reaction shots Shoot too much If you move camera pan, tilt or dolly or zoom in or out, start static and end static.

28 Camera moves Handheld cameras will be better using the wider lens for a steady picture» Telephoto close-ups will shake. A hand held camera pan can be achieved by winding up your body to the point the pan ends then twist to the spot the pan starts A camera move that reveals more information zoom out Moving camera shots- dolly, trucking, crane, steadicam, pan, tilt

29 Tripods A fluid head tripod will pan and tilt Use them!

30 Camera Support Z- Axis -An imaginary line from the tip of the camera lens to the horizon Auto focus- is best- make sure it is on Tripod- steadies the camera Use a fluid head to smooth tilts and pans Don t loose the quick release plate Studio Pedestal, sand bags, bean bags, wheel chairs, steadicam mount, or a field jib are available and create the right camera shot High- hat - A box like interim piece between film camera & tripod. Like a lot of film terms a high hat can be set on a ground, with out the tripod for a low shot

31 Terms Footage- shot video tape on camcorders EFP- Electronic Field Production Motion picture location production Electronic news gathering - ENGcan be done by independent producers, celebrity seeking stalkers, television news station staff

32 Camera Checklist Check attachable front mic for activation Balance sound on manual adjustments Check out radio mics, battery power, mic clips Always check to have charged batteries for cameras, mics, monitors, etc., before leaving for a location. For weekend shoot take battery charger

33 Rolling Camera Load with properly labeled tape Never rewind the tape, unless you have a designated Camera Assistant or Video Assist person who will re cue the tape. At this level, one may want to check tape on monitor to see if there is sound and picture Director will ask Camera ready? Director: Roll camera Camera operator: Rolling In double system sound recording Audio recorder will also call: Rolling Director will then ask to slate it Script Supervisor will call out scene and take numbers Asst Camera will hold slate in front of camera hit the clapper on the slate and call: Mark it AD or Director call Action Script Supervisor will take care of circled takes of all scenes

34 Audio and Video Audio person should check mics for every shot. That person should wear microphones and should be listening for background noise ( jets, loud voices, leaf blowers, construction noise) and let director now if it is distracting. Also check if radio mic is breaking up. Use a field monitor Use s video connection Monitor should be tuned to color perfect hue Make sure picture is not hot or cold Check for composition, lighting, cords and lights in background (believe me it happens) Script Super or director should check off all scenes completed

35 Shoot check list Check all wardrobe, props, actors, locations Check all equipment, battery charges, expendables, transportation, tapes, labeling Report on any malfunctions Make sure actors have scripts Class time will be production planning meeting We will also view dailies, plan shoot work on scripting

36 Composition Resist centering subject Balance to right or left. Use the Rule of Thirds Foreground object will add interest Lines should lead eye to subject, not other areas Avoid busy background Avoid things growing out of heads Cover a scene with wide( establishing shot), medium and close-up. Reverse, and inserts shots. Inserts are close up on a hand shake, etc.- something that moves the story Watch screen direction everything camera leftcamera right in the case of Stagecoach pages Don t cross the line

37 Composition Nose Room- space in front of the person or object Lead room area in front of moving objects Headroom area over person at top of frame Over shoulder shot or Hollywood shot OS Off stage ( in scripts Exit- If an actor walks off stage